Previous work at our laboratory has shown that the polyamines, spermidine and spermine, form a variety of N-nitrosamines upon nitrosation. Our efforts to date have dealt with the characterization of the volatile N-nitrosamines and future work will be aimed at the characterization of the non-volatile N-nitrosamines. Nitrosoproline, putrescine, spermidine and collagen have all been identified as possible precursors to nitrosopyrrolidine in fried bacon. Future work will be directed to the determination of the role of each of these potential precursors. Dimethylnitrosamine has been reported in a number of seafood products and studies will be initiated to determine the precursors and factors effecting dimethylnitrosamine formation in seafood products. Studies initiated last year will be continued to determine the dose-response curve for the carcinogenic effect of dimethylnitrosamine and nitrosopyrrolidine in rainbow trout.